January 14, 2015. The U.S. Food and Drug Administration approved the Maestro Rechargeable System for certain obese adults, the first weight loss treatment device that targets the nerve pathway between the brain and the stomach that controls feelings of hunger and fullness.

The Maestro Rechargeable System consists of a rechargeable electrical pulse generator, wire leads and electrodes implanted surgically into the abdomen. It works by sending intermittent electrical pulses to the trunks in the abdominal vagus nerve, which is involved in regulating stomach emptying and signaling to the brain that the stomach feels empty or full. Although it is known that the electric stimulation blocks nerve activity between the brain and the stomach, the specific mechanisms for weight loss due to use of the device are unknown.

External controllers allow the patient to charge the device and allow health care professionals to adjust the device’s settings in order to provide optimal therapy with minimal side effects.

The safety and effectiveness of the Maestro Rechargeable System were evaluated in a clinical trial that included 233 patients with a BMI of 35 or greater. The weight loss and adverse events of 157 patients who received the active Maestro device (the experimental group) were compared to 76 patients in the control group who received a Maestro electrical pulse generator that was not activated. The study found that after 12 months, the experimental group lost 8.5 percent more of its excess weight than the control group. About half (52.5 percent) of the patients in the experimental group lost at least 20 percent of their excess weight, and 38.3 percent of patients in the experimental group lost at least 25 percent of their excess weight.

Serious adverse events reported in the clinical study included nausea, pain at the neuroregulator site, vomiting, as well as surgical complications. Other adverse events included pain, heartburn, problems swallowing, belching, mild nausea and chest pain.